KR20130038465A - Light emitting device - Google Patents

Abstract

PURPOSE: A light emitting device is provided to reduce the thickness of a first conductive semiconductor layer by forming a recess part in a first conductive semiconductor layer region, thereby improving optical extraction efficiency. CONSTITUTION: A light emitting structure(140) includes a first conductive semiconductor layer(146), an active layer(144), and a second conductive semiconductor layer(142). A roughness or a pattern(160) is formed on the first semiconductor layer to improve optical extraction efficiency. A second electrode layer(130) is electrically connected to the second conductive semiconductor layer. A first electrode layer(120) includes a sub layer(120a) formed in the lower part of the second electrode layer and a contact electrode(120b) touching the first conductive semiconductor layer. An insulating layer(170) is formed between the first and the second electrode layer and between the first electrode layer and the light emitting structure.

Description

[0001] LIGHT EMITTING DEVICE [0002]

An embodiment relates to a light emitting element.

BACKGROUND ART Light emitting devices such as a light emitting diode (LD) or a laser diode using semiconductor materials of Group 3-5 or 2-6 group semiconductors are widely used for various colors such as red, green, blue, and ultraviolet And it is possible to realize white light rays with high efficiency by using fluorescent materials or colors, and it is possible to realize low energy consumption, semi-permanent life time, quick response speed, safety and environment friendliness compared to conventional light sources such as fluorescent lamps and incandescent lamps .

Therefore, a transmission module of the optical communication means, a light emitting diode backlight replacing a cold cathode fluorescent lamp (CCFL) constituting a backlight of an LCD (Liquid Crystal Display) display device, a white light emitting element capable of replacing a fluorescent lamp or an incandescent lamp Diode lighting, automotive headlights, and traffic lights.

In the case of a light emitting device including a via hole, the thickness of the semiconductor layer is thicker than that of a general light emitting device due to the height of the via hole. Accordingly, the travel distance that light must pass through the light emitted from the active layer to the outside is increased, and at this time, the amount of light absorbed by the semiconductor layer existing on the upper portion of the active layer increases, so that the light efficiency of the light emitting device is not good. There is a problem.

The embodiment is intended to improve the light extraction efficiency of the light emitting device by reducing the thickness of the semiconductor layer of the light emitting device.

A light emitting device according to an embodiment includes a light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer; A second electrode layer disposed under the light emitting structure and electrically connected to the second conductive semiconductor layer; And a lower layer disposed below the second electrode layer, and at least one contact electrode branched from the lower layer and penetrating the second electrode layer, the second conductive semiconductor layer, and the active layer to contact the first conductive semiconductor layer. A first electrode layer; And an insulating layer between the first electrode layer and the second electrode layer and between the first electrode layer and the light emitting structure, wherein the first conductivity type semiconductor layer is separated from the first region and the first region and is the first region. The uneven structure of the second region having a lower height is included, and the uneven portion of the uneven structure vertically overlaps the contact electrode.

Roughness or a pattern may be formed on an upper surface of the first conductive semiconductor layer.

A side surface of the light emitting structure may further include a passivation layer covering at least a portion of the second conductive semiconductor layer, the active layer and the first conductive semiconductor layer.

The width of the recessed portion of the uneven structure may be equal to or wider than the width of the contact electrode.

The width of the recessed portion of the uneven structure may be 1 to 5 times the width of the contact electrode.

Roughness may be formed in a portion of the contact electrode in contact with the first conductivity-type semiconductor layer.

One side of the second electrode layer may be exposed to the outside of the light emitting structure, and an electrode pad may be formed on the exposed portion.

The second electrode layer may include an ohmic layer and a reflective layer positioned under the second conductive semiconductor layer.

The second electrode layer may include a current spreading layer, and the electrode pad may be disposed in contact with the current spreading layer.

It may further include a passivation layer formed on the side of the recessed portion structure.

In another embodiment, a light emitting device includes: a light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer; A second electrode layer disposed under the light emitting structure and electrically connected to the second conductive semiconductor layer; And a lower layer disposed below the second electrode layer, and at least one contact electrode branched from the lower layer and penetrating the second electrode layer, the second conductive semiconductor layer, and the active layer to contact the first conductive semiconductor layer. A first electrode layer; And an insulating layer between the first electrode layer and the second electrode layer, and between the first electrode layer and the light emitting structure, wherein the first conductivity type semiconductor layer is separated from the first region and the first region in a first direction. And a second region having a thickness thinner than the first region, wherein the first region overlaps the contact electrode in the first direction.

According to the light emitting device according to the embodiment described above, as the thickness of the semiconductor layer decreases, the distance traveled until the light emitted from the active layer is emitted to the outside decreases, thereby improving light extraction efficiency of the light emitting device.

1 is a cross-sectional view showing a light emitting device according to an embodiment;
2 to 10 are views showing a manufacturing process of a light emitting device according to the embodiment,
11 is a view showing an embodiment of a light emitting device package including a light emitting device according to the embodiment,
12 is a view illustrating an embodiment of a head lamp in which a light emitting device package is disposed according to an embodiment;
13 is a diagram illustrating an example of a display device in which a light emitting device package is disposed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

In the description of the embodiment according to the present invention, in the case of being described as being formed "on or under" of each element, the upper (upper) or lower (lower) or under are all such that two elements are in direct contact with each other or one or more other elements are indirectly formed between the two elements. Also, when expressed as "on or under", it may include not only an upward direction but also a downward direction with respect to one element.

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. In addition, the size of each component does not necessarily reflect the actual size.

1 is a cross-sectional view showing a light emitting device according to an embodiment.

The light emitting device 100 according to the embodiment includes a support substrate 110, a first electrode layer 120 disposed on the support substrate 110, and a second electrode layer disposed on the first electrode layer 120. 130 and a light emitting structure 140 including a first conductive semiconductor layer 146, an active layer 144, and a second conductive semiconductor layer 142.

The light emitting device 100 includes a plurality of compound semiconductor layers, for example, a light emitting diode (LED) using a semiconductor layer of group III-V group elements, and the LED is colored to emit light such as blue, green, or red. It may be an LED or a UV LED. The emitted light of the LED may be implemented using various semiconductors, but is not limited thereto.

The light emitting structure 140 may include, for example, Metal Organic Chemical Vapor Deposition (MOCVD), Chemical Vapor Deposition (CVD), Plasma-Enhanced Chemical Vapor Deposition (PECVD), and molecular beam growth. It may be formed using a method such as Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), but is not limited thereto.

The first conductivity-type semiconductor layer 146 may be formed of a semiconductor compound, and for example, may be formed of a compound semiconductor, such as Groups 3-5 or 2-6. In addition, the first conductivity type dopant may be doped. When the first conductivity type semiconductor layer 146 is an n type semiconductor layer, the first conductivity type dopant may include Si, Ge, Sn, Se, Te as an n type dopant, but is not limited thereto. In addition, when the first conductivity type semiconductor layer is a p-type semiconductor layer, the first conductivity type dopant may include Mg, Zn, Ca, Sr, Ba, and the like as a p-type dopant.

The first conductive semiconductor layer 146 includes a semiconductor material having a composition formula of Al _x In _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1). can do. The first conductive semiconductor layer 122 may be formed of any one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP, InP.

Roughness or a pattern 160 may be formed on the top surface of the first conductivity-type semiconductor layer 146 to improve light extraction efficiency.

The active layer 144 is a layer where electrons and holes meet each other to emit light having energy determined by an energy band inherent to the active layer (light emitting layer) material.

The active layer 144 may be formed of at least one of a single well structure, a multi well structure, a quantum-wire structure, and a quantum dot structure. For example, the active layer 144 may be formed by injecting trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) to form a multi-quantum well structure. It is not limited to this.

The well layer / barrier layer of the active layer 144 may be formed of any one or more pair structures of InGaN / GaN, InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, GaAs (InGaAs) / AlGaAs, GaP (InGaP) / AlGaP. However, the present invention is not limited thereto. The well layer may be formed of a material having a lower band gap than the band gap of the barrier layer.

A conductive cladding layer (not shown) may be formed on or under the active layer 144. The conductive clad layer may be formed of a semiconductor having a band gap wider than the band gap of the barrier layer of the active layer. For example, the conductive clad layer may comprise GaN, AlGaN, InAlGaN or a superlattice structure. In addition, the conductive clad layer may be doped with n-type or p-type.

The second conductivity type semiconductor layer 142 may be formed of a semiconductor compound, for example, a group III-V compound semiconductor doped with a second conductivity type dopant. A second conductive semiconductor layer 142, for example, having a compositional formula of _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0≤y≤1, 0≤x + y≤1) It may include a semiconductor material. When the second conductive semiconductor layer 142 is a p-type semiconductor layer, the second conductive dopant may be a p-type dopant and may include Mg, Zn, Ca, Sr, and Ba. In addition, when the second conductivity type semiconductor layer 142 is an n type semiconductor layer, the second conductivity type dopant may include Si, Ge, Sn, Se, Te as an n type dopant, but is not limited thereto.

In the present exemplary embodiment, the first conductive semiconductor layer 146 may be an n-type semiconductor layer, and the second conductive semiconductor layer 142 may be a p-type semiconductor layer. Alternatively, the first conductive semiconductor layer 146 may be a p-type semiconductor layer, and the second conductive semiconductor layer 142 may be an n-type semiconductor layer. In addition, an n-type semiconductor layer (not shown) may be formed on the second conductive semiconductor layer 142 when a semiconductor having a polarity opposite to that of the second conductive type, for example, the second conductive semiconductor layer is a p-type semiconductor layer. Can be. Accordingly, the light emitting structure may be implemented as any one of an n-p junction structure, a p-n junction structure, an n-p-n junction structure, and a p-n-p junction structure.

The support substrate 110 supports the light emitting structure 140 and may be a conductive substrate or an insulating substrate. In addition, it may be formed of a material having high electrical conductivity and thermal conductivity. For example, the support substrate 110 is a base substrate having a predetermined thickness, and is composed of molybdenum (Mo), silicon (Si), tungsten (W), copper (Cu), and aluminum (Al). It can be made of a material selected from or alloys thereof, and also, gold (Au), copper alloy (Cu Alloy), nickel (Ni), copper-tungsten (Cu-W), carrier wafers (e.g. GaN, Si, Ge, GaAs, ZnO, SiGe, SiC, SiGe, Ga ₂ O _3, etc.) or a conductive sheet may be optionally included.

The first electrode layer 120 is formed on the support substrate 110. The first electrode layer 120 may be formed of a metal, and may include at least one of an ohmic layer, a reflective layer, and a bonding layer. The first electrode layer 120 may be in ohmic contact with the first semiconductor layer 146, which will be described later, using a reflective metal or in ohmic contact using a conductive oxide.

The first electrode layer 120 may be made of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf, or an optional combination thereof. In addition, the first electrode layer 120 may be formed as a single layer or multiple layers of a reflective electrode material having ohmic characteristics. When the first electrode layer 120 plays an ohmic role, the ohmic layer may not be formed.

The first electrode layer 120 is formed of the metals, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), and IGTO. (indium gallium tin oxide), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrOx, RuOx, RuOx / ITO, Ni / IrOx / Au, or Ni / IrOx / Au / ITO It may include at least one of, but is not limited to such materials.

In addition, the first electrode layer 120 may include a bonding layer, wherein the bonding layer is a barrier metal or a bonding metal, for example, Ti, Au, Sn, Ni, Cr, Ga, In, Bi, Cu, Ag And Ta at least.

When the first electrode layer 120 does not include a bonding layer, as shown in FIG. 1, a separate bonding layer 115 may be formed to be coupled to the support substrate 110. The bonding layer 115 may be formed of, for example, a material selected from the group consisting of Au, Sn, In, Ag, Ni, Nb, and Cu or an alloy thereof, but is not limited thereto.

The second electrode layer 130 is formed on the lower layer 120a of the first electrode layer 120, which will be described later, and an insulating layer 170 is formed between the second electrode layer 130 and the first electrode layer 120. The first electrode layer 120 and the second electrode layer 130 are electrically insulated.

The second electrode layer 130 may be a structure of an ohmic layer / reflection layer / junction layer, a laminated structure of an ohmic layer / reflection layer, or a structure of a reflective layer (including ohmic) / junction layer, but is not limited thereto. In addition, the second electrode layer 130 may include a current spreading layer. For example, the second electrode layer 130 may have a structure in which the current spreading layer 136, the reflective layer 134, and the ohmic layer 132 are sequentially stacked on the insulating layer 170.

 The current spreading layer 136 may be formed of a metal having high electrical conductivity, and may be electrically connected to the electrode pad 190 to be described later to supply current to the second conductive semiconductor layer 142. The current spreading layer 136 may selectively include at least one selected from, for example, Ti, Au, Ni, In, Co, W, Fe, and the like, but is not limited thereto.

The reflective layer 134 is disposed on the current spreading layer 136 and may be formed of a reflective material having a reflectivity of 50% or more. The reflective layer 134 is formed from, for example, a material consisting of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf, and a combination thereof, or It may be formed in multiple layers using a light transmissive conductive material such as IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO. In addition, the reflective layer 134 may be laminated with IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag / Ni, or the like. In addition, when the reflective layer 134 is formed of a material in ohmic contact with the light emitting structure (eg, the second conductivity-type semiconductor layer 142), the ohmic layer 132 described later may not be separately formed. I do not.

The ohmic layer 132 may be formed in contact with the second conductivity-type semiconductor layer 142. Since the second conductivity-type semiconductor layer 142 has a low impurity doping concentration and high contact resistance, and thus may not have good ohmic characteristics with the metal, the ohmic layer 132 may be formed to improve such ohmic characteristics. It is not.

Since the ohmic layer 132 is disposed between the light emitting structure 140 and the reflective layer 134, the ohmic layer 132 may be formed as a transparent electrode, or may be formed as a layer or a plurality of patterns.

The ohmic layer 132 may be about 200 angstroms thick. The ohmic layer 132 may be formed of a light transmissive conductive layer and a metal, for example, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), and indium aluminum zinc oxide (AZO). ), Indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IZON (IZO Nitride), AGZO (Al-Ga) ZnO), IGZO (In-Ga ZnO), ZnO, IrOx, RuOx, NiO, RuOx / ITO, Ni / IrOx / Au, or Ni / IrOx / Au / ITO, Ag, Ni, Cr, Ti, Al, Rh, At least one of Pd, Ir, Sn, In, Ru, Mg, Zn, Pt, Au, and Hf may be formed, but is not limited thereto.

The first electrode layer 120 is branched from the lower layer 120a and the lower layer 120a to penetrate the second electrode layer 120, the second conductive semiconductor layer 142, and the active layer 144 to form the first conductive type. One or more contact electrodes 120b in contact with the semiconductor layer 146 are included.

The plurality of contact electrodes 120b may be branched from the lower layer 120a of the first electrode layer 120 to be spaced apart from each other. When there are a plurality of contact electrodes 120b, the current supply to the first conductivity-type semiconductor layer 146 can be smoothly performed. When viewed from the top, the contact electrode 120b may be at least one of a radial pattern, a cross pattern, a line pattern, a curved pattern, a loop pattern, a ring pattern, and a ring pattern, but is not limited thereto.

An ohmic layer may be formed on the contact electrode 120b to make ohmic contact with the first conductivity-type semiconductor layer 146.

Roughness 122 may be formed in a portion of the contact electrode 120b in contact with the first conductivity-type semiconductor layer 146. The roughness 122 forms a roughness in a random shape at a portion in contact with the first conductivity-type semiconductor layer 146. The roughness 122 may be formed by a wet etching process or a dry etching process.

The roughness 122 increases the area where the first electrode layer 120 and the first conductive semiconductor layer 146 contact each other. As the contact area between the first electrode layer 120 and the first conductivity-type semiconductor layer 146 increases, the contact area of the electrode may be increased, thereby improving electrical characteristics of the light emitting device 100. In addition, the roughness 122 may increase the adhesion between the first electrode layer 120 and the first conductivity-type semiconductor layer 146, thereby improving reliability of the light emitting device 100.

An insulating layer 170 is formed between the first electrode layer 120 and the second electrode layer 130 and on the sidewall of the contact electrode 120b of the first electrode layer 120, thereby forming different layers from the first electrode layer 120. Electrical insulation is cut off between (130, 142, 144).

The insulating layer 170 may be made of non-conductive oxide or nitride. As an example, the insulating layer 170 may be formed of a silicon oxide (SiO ₂ ) layer, an oxynitride layer, or an aluminum oxide layer.

One region of the second electrode layer 130, for example, one region of the current spreading layer 136 of the second electrode layer 130 may be exposed to the outside of the light emitting structure 140. The electrode pad 190 may be formed on one side of the exposed second electrode layer 130.

For example, the electrode pad 190 may include at least one of aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), copper (Cu), and gold (Au). Can be formed.

The passivation layer 180 may be formed on the side surface of the light emitting structure 140. For example, the passivation layer 180 may be disposed to cover a portion of the second conductive semiconductor layer 142, the active layer 144, and the first conductive semiconductor layer 146.

A passivation layer (not shown) may also be formed on the side surface of the recessed portion 148a of the concave-convex structure 148 described later in the first conductive semiconductor layer 146.

The passivation layer 180 is formed of an insulating material to prevent electrical short between the light emitting structure 140 and the electrode pad 190, and may be formed of the same material as the material of the insulating layer 170.

The first conductive semiconductor layer 146 includes a concave-convex structure 148 including a concave portion 148a and a convex portion 148b having a height lower than that of the concave portion 148a, and the concave portion 148a includes a first electrode layer ( It may overlap vertically with the contact electrode 120b of 120.

In addition, the shape of the recess 148a may be one of a cylinder shape, a cone shape, a pyramid shape, a square pillar shape, and a semi-sphere shape, but is not limited thereto.

Conventionally, since the first conductivity type semiconductor layer is formed thick so as to secure an area equal to the height of the contact electrode of the first electrode layer, the thickness of the light emitting device is thick.

When the thickness of the first conductivity-type semiconductor layer 146 positioned on the upper portion of the light emitting structure 140 is thick, the distance traveled until the light emitted from the active layer 144 is emitted to the outside increases. In this case, a portion of light is absorbed by the first conductivity type semiconductor layer, thereby reducing the light extraction efficiency of the light emitting device.

In an embodiment, the first conductive semiconductor layer 146 has the uneven structure 148. In the recessed part 148a, a predetermined height difference H _{2 from} the top surface of the contact electrode 120b is secured to ensure reliability of the light emitting device. And a convex portion 148b in a region on the first conductivity-type semiconductor layer 146 where the contact electrode 120b is not present, thereby lowering the height H ₃ of the first conductivity-type semiconductor layer 146. The light extraction efficiency of the light emitting device 100 can be improved.

A constant height difference H ₂ must be maintained between the upper surface of the first conductive semiconductor layer 146 and the contact electrode 120b. If the top surface of the first conductive semiconductor layer 146 is too close to the contact electrode 120b, the contact electrode 120b may be formed during the texturing process of forming a roughness or pattern on the top surface of the first conductive semiconductor layer 146. This is because some of the) may be exposed to the outside, causing an electrical short. The height difference (H ₂ ) can maintain 1 ~ 5um so as not to interfere with the light extraction while ensuring the reliability of the light emitting device.

In the uneven structure 148 of the first conductive semiconductor layer 146, the height difference H ₃ between the convex portion 148b and the active layer 144 of the light emitting structure 140 must also be maintained to a certain degree. If the top surface of the first conductive semiconductor layer 146 is too close to the active layer 142, the active layer 144 may be formed during the texturing process of forming a roughness or pattern on the top surface of the first conductive semiconductor layer 146. This is because exposure to the outside may reduce the reliability of the light emitting device. The height difference H ₃ may maintain 0.5 to 4 μm so as not to interfere with light extraction while ensuring reliability of the light emitting device.

In addition, the total height H ₁ of the light emitting structure 140 may be 1 ~ 5um.

The recessed portion 148a of the uneven structure 148 vertically overlaps the contact electrode 120b of the first electrode layer 120, and the width W ₂ of the recessed portion 148a is the width W of the contact electrode 120b. May be equal to or wider than ₁ ).

The width W ₂ of the recess 148a may vary depending on the width between the contact electrodes 120b formed by branching from the lower layer 120a of the first electrode layer 120. ₂ ) may be 1 to 5 times the width W ₁ of the contact electrode 120b.

According to the embodiment, since the recess 148a of the first conductivity-type semiconductor layer 146 vertically overlaps the contact electrode 120b and maintains a constant height difference H ₂ , reliability of the light emitting device can be ensured. Improving the light extraction efficiency of the light emitting device by forming the convex portion 148b in the region of the first conductivity type semiconductor layer 146 where the contact electrode 120b is not located to reduce the thickness of the first conductivity type semiconductor layer 146. can do.

The uneven structure 148 of the first conductive semiconductor layer 146 forms a photoresist layer on the top surface of the first conductive semiconductor layer 146, and covers the mask on which the pattern is formed, and then irradiates ultraviolet rays. Can be formed.

The PR layer may use an aspect photosensitive film that melts when the irradiated portion is developed or a negative photoresist that is left when the irradiated portion is developed.

In addition, since the light emitted from the active layer 144 is emitted not only on the top surface of the first conductivity-type semiconductor layer 146 but also on the side surface of the recess 148a, the uneven structure 140 is formed on the first conductivity-type semiconductor layer 146. ), The area in which light is emitted can be increased to improve optical characteristics of the light emitting device.

2 to 10 are views showing a manufacturing process of the light emitting device according to the embodiment. Hereinafter, an embodiment of a manufacturing method of a light emitting device will be described with reference to FIGS. 2 to 10.

As shown in FIG. 2, the light emitting structure 140 is grown on the substrate 101.

The substrate 101 may be formed of a material suitable for growing a semiconductor material or a carrier wafer. In addition, it may be formed of a material having excellent thermal conductivity, and may be a conductive substrate or an insulating substrate. The substrate 101 may use, for example, at least one of sapphire (Al ₂ O ₃ ), SiC, GaAs, GaN, ZnO, Si, GaP, InP, Ge, and Ga ₂ 0 ₃ . An uneven structure may be formed on the substrate 101, but is not limited thereto. Impurities on the surface may be removed by wet cleaning the substrate 101.

The light emitting structure 140 may be formed by sequentially growing the first conductivity type semiconductor layer 146, the active layer 144, and the second conductivity type semiconductor layer 142 on the substrate 101.

The light emitting structure 140 may include, for example, Metal Organic Chemical Vapor Deposition (MOCVD), Chemical Vapor Deposition (CVD), Plasma-Enhanced Chemical Vapor Deposition (PECVD), and molecular beam growth. It may be formed using a method such as Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), but is not limited thereto.

The first conductive semiconductor layer 146 is grown to a thickness D ₁ and is thicker than the thickness of the first conductive semiconductor layer formed in a general light emitting device having no contact electrode.

A buffer layer (not shown) may be grown between the light emitting structure 140 and the substrate 101 to mitigate the difference in lattice mismatch and thermal expansion coefficient of the material. The material of the buffer layer may be formed of at least one of Group III-V compound semiconductors such as GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN. An undoped semiconductor layer may be formed on the buffer layer, but the present invention is not limited thereto.

As shown in FIG. 3, the second electrode layer 130 is formed on the second conductivity-type semiconductor layer 142. The second electrode layer 130 may be any one of an ohmic layer / reflection layer / junction layer, an ohmic layer / reflection layer, and a reflective layer / junction layer, and may include a current spreading layer.

For example, the ohmic layer 132 and the reflective layer 134 may be formed on the second conductive semiconductor layer 142, and the current spreading layer 136 may be formed on the reflective layer 134. In this case, the current spreading layer 136 may be grown wider than the width of the ohmic layer 132 and the reflective layer 134, and one side of the current spreading layer 136 is in contact with the second conductive semiconductor layer 142. Afterwards, a current may be supplied to the second conductivity-type semiconductor layer 142.

The ohmic layer 132, the reflective layer 134, and the current spreading layer 136 may be formed, for example, by any one of electron beam (E-beam) deposition, sputtering, and plasma enhanced chemical vapor deposition (PECVD). It may be formed, but not limited thereto.

3 is only an example, and an area in which the ohmic layer 132, the reflective layer 134, and the current spreading layer 136 are formed may be variously selected.

As shown in FIG. 4, at least one via hole exposing the first conductive semiconductor layer 146 through the second electrode layer 130, the second conductive semiconductor layer 142, and the active layer 144. 212, 214. Roughness 122 may be formed at the bottom of the via holes 212 and 214.

The via holes 212 and 214 are formed using, for example, a photolithography process and an etching process. The via holes 212 and 214 are exposed by selectively etching the second electrode layer 130 to expose the second conductive semiconductor layer 142. The second conductive semiconductor layer 142 and the lower active layer 144 may be etched to expose the first conductive semiconductor layer 146.

The roughness 122 may be formed by performing a dry etching or PEC etching process on the first conductive semiconductor layer 146 exposed by the via holes 212 and 214.

Next, as shown in FIG. 5, an insulating layer 170 is formed on the top surface of the second electrode layer 130 and the side surfaces of the via holes 212 and 214.

6, the first electrode layer 120 is formed to fill the via holes 212 and 214 with a conductive material to be in contact with the first conductivity-type semiconductor layer 146. At this time, the conductive material is also filled in the roughness 116 portion of the bottom surface of the via holes 212 and 214.

The conductive material may be a metal having high electrical conductivity, and for example, at least one of aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), copper (Cu), and gold (Au). It may be made, including but not limited to.

The conductive material filled in the via holes 212 and 214 becomes the contact electrode 120b of the first electrode layer 120.

As illustrated in FIG. 7, the support substrate 110 is disposed on the first electrode layer 120. The support substrate 110 may be formed by a bonding method, a plating method, or a deposition method. When the supporting substrate 110 is formed by a bonding method, for example, the first electrode layer 120 and the supporting substrate 110 may be attached using a separate bonding layer 115.

Then, as shown in FIG. 8, the substrate 101 is separated. The substrate 101 may be removed by laser lift off (LLO) using an excimer laser or the like, or may be performed by dry and wet etching.

For example, when the laser lift-off method focuses and irradiates excimer laser light having a predetermined wavelength toward the substrate 101, thermal energy is applied to the interface between the substrate 101 and the light emitting structure 140. As the interface is separated and separated into gallium and nitrogen molecules, the substrate 101 is momentarily separated at the portion where the laser light passes.

Next, as illustrated in FIG. 9, an isolation etching is performed on the unit light emitting structure 140 to be separated into units of respective light emitting devices. Isolation etching may be performed by a dry etching method such as, for example, an inductively coupled plasma (ICP). A portion of the second electrode layer 130 may be opened to the outside of the light emitting structure 140 by isolation etching. For example, the light emitting structure 140 may be etched by an isolation etching to open one side of the second electrode layer 130, that is, a part of the edge.

Thereafter, a PR layer 250 is formed on the first conductive semiconductor layer 146. The PR layer 250 may be formed using an aspect photosensitive film that melts when a portion irradiated with light is developed, or a negative photoresist layer that is left when the portion irradiated with light is developed. In FIG. 9, an aspect photosensitive film was used as an example.

After the PR layer 250 is formed, the pattern formed on the mask 260 is covered on the top, and then irradiated with ultraviolet rays, the pattern formed on the mask 260 is developed on the PR layer 250 to pass through the mask 260. The portion of the PR layer 250 irradiated with light melts. After the etching is performed, the uneven structure 148 is formed on the first conductive semiconductor layer 146 as shown in FIG. 10.

As described above, the recessed portion 148a of the uneven structure 148 is formed to vertically overlap with the contact electrode 120b.

In the exemplary embodiment, the uneven structure 148 is formed after the isolation etching is performed, but the process order is not limited.

An electrode pad 190 is formed on one side of the second electrode layer 130 opened and exposed by the isolation etching.

In addition, the passivation layer 180 covering the side surface of the light emitting structure 140 is formed.

The passivation layer 180 may be formed to cover the side surface of the light emitting structure 140, but is not limited thereto. The passivation layer 180 may be formed to cover a portion of the side surface and the upper surface of the light emitting structure 140. A passivation layer (not shown) may also be formed on the side surface of the recess 148a of the first conductivity type semiconductor layer 146.

Then, the roughness or the pattern 160 is formed on the upper surface of the first conductive semiconductor layer 146.

11 is a view showing an embodiment of a light emitting device package including a light emitting device according to the embodiment.

The light emitting device package 300 according to the embodiment includes a body 310 having a cavity, a first lead frame 321 and a second lead frame 322 installed in the body 310, and the body 310. The light emitting device 100 according to the above-described embodiments is installed and electrically connected to the first lead frame 321 and the second lead frame 322, and a molding part 340 formed in the cavity.

The body 310 may be formed including a silicon material, a synthetic resin material, or a metal material. When the body 310 is made of a conductive material such as a metal material, although not shown, an insulating layer is coated on the surface of the body 310 to prevent an electrical short between the first and second lead frames 321 and 322. Can be.

The first lead frame 321 and the second lead frame 322 are electrically separated from each other, and supplies a current to the light emitting device 100. In addition, the first lead frame 321 and the second lead frame 322 may increase the light efficiency by reflecting the light generated by the light emitting device 100, heat generated by the light emitting device 100 Can be discharged to the outside.

The light emitting device 100 may be installed on the body 310 or may be installed on the first lead frame 321 or the second lead frame 322. In the present embodiment, the first lead frame 321 and the light emitting device 100 are directly energized, and the second lead frame 322 and the light emitting device 100 are connected through a wire 330. The light emitting device 100 may be connected to the lead frames 321 and 322 by a flip chip method or a die bonding method in addition to the wire bonding method.

The molding part 340 may surround and protect the light emitting device 100. In addition, a phosphor 350 is included on the molding part 340 to change the wavelength of light emitted from the light emitting device 100.

The phosphor 350 may include a garnet-based phosphor, a silicate-based phosphor, a nitride-based phosphor, or an oxynitride-based phosphor.

For example, the garnet-base phosphor is _{YAG (Y 3 Al 5 O 12} : Ce 3 +) or TAG: may be a _{(Tb 3 Al 5 O 12 Ce} 3 +), wherein the silicate-based phosphor is (Sr, Ba, _{Mg, Ca) 2 SiO 4:} Eu 2 + one can, the nitride-based fluorescent material is CaAlSiN ₃ containing SiN: Eu ^{2 +} one can, Si ₆ of the oxynitride-based fluorescent material includes SiON _{- x} Al _x O _x N _{8 -x} : Eu ^{2 +} (0 <x <6).

Light in the first wavelength region emitted from the light emitting device 100 is excited by the phosphor 250 and converted into light in the second wavelength region, and the light in the second wavelength region passes through a lens (not shown). The light path can be changed.

A plurality of light emitting device packages according to the embodiment may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, and the like, which are optical members, may be disposed on an optical path of the light emitting device package. Such a light emitting device package, a substrate, and an optical member can function as a light unit. Another embodiment may be implemented as a display device, an indicator device, or a lighting system including the semiconductor light emitting device or the light emitting device package described in the above embodiments, and for example, the lighting system may include a lamp or a street lamp. .

Hereinafter, a head lamp and a backlight unit will be described as an embodiment of a lighting system in which the above-described light emitting device package is disposed.

12 is a view illustrating an embodiment of a head lamp in which a light emitting device package is disposed according to an embodiment.

As shown in FIG. 12, the headlamp 700 includes a lens after the light emitted from the light emitting module 710 in which the light emitting device package is disposed is reflected by the reflector 720 and the shade 730. It may pass through 740 and face the front of the vehicle body.

The light emitting device package included in the light emitting module 710 may include a plurality of light emitting devices, but is not limited thereto.

In the light emitting device package including the light emitting device according to the embodiment, the light extraction efficiency is improved due to the reduction in the thickness of the first conductivity type semiconductor layer, so that the light efficiency of the light emitting module 710 may be improved as a whole.

FIG. 13 is a diagram illustrating a display device in which a light emitting device package according to an embodiment is disposed.

As shown in FIG. 13, the display device 800 according to the exemplary embodiment is disposed in front of the light source modules 830 and 835, the reflector 820 on the bottom cover 810, and the reflector 820. A light guide plate 840 for guiding light emitted from the light source module to the front of the display device, a first prism sheet 850 and a second prism sheet 860 disposed in front of the light guide plate 840, and the second prism And a panel 870 disposed in front of the sheet 860 and a color filter 880 disposed throughout the panel 870.

The light source module includes the above-described light emitting device package 835 on the circuit board 830. Here, the circuit board 830 may be a PCB or the like, and the light emitting device package 835 is the same as that described with reference to FIG.

The bottom cover 810 may receive components in the display device 800. The reflective plate 820 may be provided as a separate component as shown in the figure, or may be provided in the form of a high reflective material on the rear surface of the light guide plate 840 or the front surface of the bottom cover 810. Do.

Here, the reflection plate 820 can be made of a material having a high reflectance and can be used in an ultra-thin shape, and polyethylene terephthalate (PET) can be used.

The light guide plate 840 scatters light emitted from the light emitting device package module so that the light is uniformly distributed over the entire screen area of the LCD. Accordingly, the light guide plate 830 is made of a material having a good refractive index and transmittance. The light guide plate 830 may be formed of polymethyl methacrylate (PMMA), polycarbonate (PC), or polyethylene (PE). In addition, the light guide plate may be omitted, and thus an air guide method in which light is transmitted in the space on the reflective sheet 820 may be possible.

The first prism sheet 850 is formed of a translucent and elastic polymer material on one surface of the support film, and the polymer may have a prism layer in which a plurality of three-dimensional structures are repeatedly formed. Here, the plurality of patterns may be provided in the stripe type and the valley repeatedly as shown.

In the second prism sheet 860, the direction of the floor and the valley of one surface of the support film may be perpendicular to the direction of the floor and the valley of one surface of the support film in the first prism sheet 850. This is to evenly distribute the light transmitted from the light source module and the reflective sheet in all directions of the panel 870.

In the present embodiment, the first prism sheet 850 and the second prism sheet 860 form an optical sheet, which is composed of another combination, for example, a micro lens array or a diffusion sheet and a micro lens array. Or a combination of one prism sheet and a micro lens array.

The liquid crystal display panel (Liquid Crystal Display) may be disposed on the panel 870, in addition to the liquid crystal display panel 860 may be provided with other types of display devices that require a light source.

The panel 870 is a state in which the liquid crystal is located between the glass body and the polarizing plate is placed on both glass bodies in order to use the polarization of light. Here, the liquid crystal has an intermediate property between a liquid and a solid, and liquid crystals, which are organic molecules having fluidity like a liquid, are regularly arranged like crystals. The liquid crystal has a structure in which the molecular arrangement is changed by an external electric field And displays an image.

A liquid crystal display panel used in a display device is an active matrix type, and a transistor is used as a switch for controlling a voltage supplied to each pixel.

The front surface of the panel 870 is provided with a color filter 880 to transmit the light projected from the panel 870, only the red, green and blue light for each pixel can represent an image.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

101: substrate 110: support substrate
115: bonding layer 120: first electrode layer
120a: lower layer 120b: contact electrode
130: second electrode layer 132: ohmic layer
134: reflective layer 136: current spreading layer
140: light emitting structure 142: second conductive semiconductor layer
144: active layer 146: first conductive semiconductor layer
148: uneven structure 148a: uneven portion
148b: iron 170: insulating layer
180: passivation layer 190: electrode pad
212, 214: Via Hole 250: PR floor
310: package body 321, 322: first and second lead frames
330: wire 340: molding part
350: phosphor 710: light emitting module
720: Reflector 730: Shade
800: display device 810: bottom cover
820: reflector 840: light guide plate
850: first prism sheet 860: second prism sheet
870: panel 880: color filter

Claims (12)

A light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer;
A second electrode layer disposed under the light emitting structure and electrically connected to the second conductive semiconductor layer;
And a lower layer disposed below the second electrode layer, and at least one contact electrode branched from the lower layer and penetrating the second electrode layer, the second conductive semiconductor layer, and the active layer to contact the first conductive semiconductor layer. A first electrode layer; And
An insulating layer between the first electrode layer and the second electrode layer and between the first electrode layer and the light emitting structure,
The first conductive semiconductor layer may include a concave-convex structure of a first region and a second region, which is distinguished from the first region, and has a lower height than the first region, and the concave-convex structure of the concave-convex structure vertically overlaps the contact electrode. Light emitting device. The method of claim 1,
A light emitting device having a roughness or a pattern formed on an upper surface of the first conductive semiconductor layer. The method of claim 1,
And a passivation layer covering at least a portion of a second conductive semiconductor layer, an active layer, and a first conductive semiconductor layer on a side surface of the light emitting structure. The method of claim 1,
A light emitting element in which the width of the recessed portion of the uneven structure is equal to or wider than the width of the contact electrode. The method of claim 4, wherein
The width of the recessed portion of the uneven structure is 1 to 5 times the width of the contact electrode. The method of claim 1,
And a roughness formed in a portion of the contact electrode in contact with the first conductivity type semiconductor layer. The method of claim 1,
One side of the second electrode layer is exposed to the outside of the light emitting structure, the light emitting device in which the electrode pad is formed on the exposed portion. The method of claim 1,
The second electrode layer includes an ohmic layer and a reflective layer positioned below the second conductive semiconductor layer. The method of claim 7, wherein
The second electrode layer includes a current spreading layer, and the electrode pad is disposed in contact with the current spreading layer. The method of claim 1,
The light emitting device further comprising a passivation layer formed on the side of the recessed portion structure. The method of claim 1,
The recessed portion of the concave-convex structure has a cylindrical shape, a conical shape, a pyramid shape, a square pillar shape, or a semi-sphere shape. A light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer;
A second electrode layer disposed under the light emitting structure and electrically connected to the second conductive semiconductor layer;
And a lower layer disposed below the second electrode layer, and at least one contact electrode branched from the lower layer and penetrating the second electrode layer, the second conductive semiconductor layer, and the active layer to contact the first conductive semiconductor layer. A first electrode layer; And
An insulating layer between the first electrode layer and the second electrode layer and between the first electrode layer and the light emitting structure,
The first conductivity type semiconductor layer may include a first region and a second region that is separated from the first region and is thinner than the first region in a first direction, wherein the first region includes the contact electrode and the first region. Light emitting element overlapping in the direction.

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